Treatment of phosphates.



UNITED STATES PATENT OFFICE.

NATHANIEL I. PRAT'IL OF ATLANTA, GEORGIA, ASSIGNOR TO PRATT PROCESS COM- I PANY, ORATLANTA, GEORGIA, A CORPORATION OF GEORGIA. J

No Drawing.

To all whom it may concern:

Be it known that I, NATHANIEL PRATT, a citizen of the United States, residmg at Atlanta, in the'county of Fulton'and State of Georgia, have invented certain new and useful Improvements in the Treatment of Phosphates of which the following 1s a specification.

My invention relates to the treatment of phosphates.

My invention is pred1cated,-pr1mar1ly, upon the discovery that certain earthy deposits with which I have become familiar differ substantially from other known phosphate-deposits in at least two respects: First, they are not in the usual form of rock; and, secondly, they nclude, as shown by analysis, about thlrty-four per cent. (34%) of calcium sulfate, approximately, and about sixty per cent. (60%), approxlmately, of what is commercially known as bone phosphate of lime, the last-mentioned being very sparingly soluble 111 water. It

' is the. valuable constituent desired for the manufacture of fertilizers; and, in consequence, the primary object of my invention is to separate from it the calcium sulfate and thereby produce a product which is IlCh in phosphate. By reason of the fact that these particular deposits include practlcally no impuritiessuch as clay, sand, etc.1n

, the sense that such impurities usually exist in other deposits and which have to be taken into consideration in known processes, I am enabled to utilize the process hereafter described with great success. Thereby, I not onlyam able materially to reduce the cost of production, but the product obtained is exceedingly rich in its inclusion of a des red proportionate amount of calcium phosphate.

As is generally known to those familiar With the art, native phosphates have heretofore been prepared for use by washmg with water. By a system of flushing, this waterremoves the sand and clay. The product of my invention is distinguished from these so-called washed phosphates, as will readily be understood bythose skilled in the art.

I have found, by experiments, that the methods heretofore practiced will not suliice to produce the best results in connect1on with the native phosphates hereinabove referred to. .In thefirst place, the material is loose, light-"and earthy, and there are, as already stated, none of the usual lmpurlties,

Specification of Letters Patent.

Application filed January 27, 1911.

,I have discovered that it and, therefore,

. TREATMENT OF PHOSPHATES.

PatentedJan.9,1912. Serial in. 804,998.

the phosphate because it is not a valuable,

fertilizer-ingredient. It can not, however, be separated therefrom at all, in suspension in water like sand and clay, but, by experience, is soluble in fresh water to a slight extent. It is, however, readily soluble in saline solutions, and, particularly, in that class of solutions comprising, or which includes, sea water. I have also discovered that this sea water has little or no practical action on the calcium phosphate present in the mass. In view of the discoveries of these peculiar characteristics of these particular native phosphatic deposits, I propose, as a method of treating the same, to subject said native phosphates to the action of a saline solution, preferably, sea water, either by mixingthe same with the material and settling it out, and draining off the Water to thereby carry the calcium sulfate in solution; or by percolation through the mass; or, in fact, by any other suitable means of treatment, the object being, always, to dissolve the calcium sulfate out of the mass and leave the phosphate present. The action of thesea water is to dissolve the calcium sulfate out of the phosphatic aggresuch as sand, clay, etc., present in the de gants. leaving them in porous condition. I

have found, by this novel method of solution and drainage, that all of the calcium sulfate can be removed, and With'the practical result that, a mass which originally contained only 60% of calcium phosphate is raised to a richness of approximately ninety per cent. As is generally known, the measure of the value of phosphates for the manufacture of fertilizers is the percentage of phos- "phates they contain. Hence, the product of my invention is of very great value by reason of its richness therein. So'far as I am aware, no native deposit of phosphates, other than that above-mentioned, has ever been found which contains calcium sulfate in appreciable quantities none in which the calcium sulfate plays such an important part as to make'ita desideratum to remove it. Again, I know ofno other phosphatic deposit which contains a practically valueless ingredient which is appreciably soluble in water and another ingredient which is valuable and which has the characteristic of not appreciably dissolving irrwater. Moreover, I am unaware of any other deposit wherein the mass embodies practically no other im urities of the kind already specified. T erefore, it is novel procedure to subject such a masscontaining calcium phosphate and cal cium sulphate to thedissolving action of water, thereby rendering the latter in solution without practically affecting the phosphates.

By my invention, I am therefore enabled to utilize, wlth new results,"saline solut ons,

of which sea water furnishes a preferable type, to enrich native phosphates contain:

ing sulfates and this processI claim broadly.

\Vhile I have herein described my new method in detail, it is to be understood that I do not limit myself to such details of procedure exce t insofar as these may be specified in the c aims. Having thus fully described my inven-' tion, the procedure followed thereunder, and the results produced, what I claim as new and desire to secure by Letters-Patent of the United States is:

phates containing 1. Themethod of enriching native phosphates containing sulfates, which consists in subjecting the same to the solvent action of water toseparate the sulfates from the phosphates, and then draining off the water containing the sulfates.

2. The method of treating native phossulfates' which consists in subjecting the same to the solvent action of a saline solution toseparate the sulfates sea water and signature in presence 5. The method of treatin phates containing sulfates, w 'ch consists m subjecting the same to the solvent action of subsequently .draining ofi from the mass the water containing the S111. fates.

*6. The hereindescribed process of enriching a phosphatm mass containing calcium sulfate soluble in water and calclum phosphate insoluble in water,\which consists in natiie pho ssubjectingsaid mass to the action of sea water to dissolve the sulfates, ing said sulfatecharged phosphates. I 4

7 The herein-described processof enrichand then separatwater from the ing a phosphatic mass to aproximately 90% bone phosphate of lime, whichv consists in subjecting native phosphates containing sulfates'to the action separating the sulfate-containing water from the mass. 1

8. The hereindescribed process of treating native phosphates which consists in disassociating the calcium s calcium phosphate through the medium of ofsea water and then ulfate from the I sea water to render the sulfate soluble, and y then separating the-sulfate solution our the phosphates which are insoluble in sa1d water. r

. 9. The method of treating native phosphates containing sulfates, which consists in separating the sulfates from the phosphates.

10. The method of treating native phosphates containing sulfates, which consists in separating the sulfates from the phosphates,

said separation being effected by subjecting the same to the solvent action of water and, then, draining off the sulfate-impregnated water.

11. The method of treating phates containing sulfates, which consists in separating the sulfates from the phosphates, such separation being elfected by sub ecting the same to the solvent action of sea-water and subsequently draining oil from the mass the water containing the sulfate.

In testimony whereof I have afiixed my of two witnesses. 1 NATHANIEL P. PRATT.' Witnesses: v

C. H. BBOTHZERTON,

P. G. KEENEY.

rative phos- 

